Field of the Invention
The present invention relates to an adhesive tape for connecting secondary battery electrodes, and more particularly, to an adhesive tape for connecting secondary battery electrodes which prevents an adhesive from leaking to electrodes during electrode processing processes even though the adhesive tape for connecting the electrodes is adhered or which prevents the adhesive from leaking to the electrodes wound near the adhesive tape in a case that the electrode substrates are wound in a roll type in order to continuously connect electrode substrates of the front and rear ends during a secondary battery electrode manufacturing process, thereby preventing the electrodes from being damaged and from being unacceptable.
Background Art
In general, a secondary battery is a rechargeable battery which can be continuously used through recharging even after it converts energy into electric energy because using a charging material, which is repeatable the oxidation-reduction action between an electric current and a material several times, differently from a first battery which is wasted when it is used once.
Most of secondary batteries used in electronic handheld devices, such as mobile phones, digital cameras or others, are configured such that an anode substrate and a cathode substrate respectively having active material layers are wound together with a separator and are inserted into a battery housing and an electrolyte is injected into the housing. Such secondary batteries use the electrochemical reaction generated between molecules of the electrolyte and active materials when the anode and the cathode are connected with each other.
As the secondary batteries, there are nickel-cadmium batteries, nickel-hydride batteries, nickel-zinc batteries, lithium-ion batteries, lithium-polymer batteries and lithium-sulfur batteries according to which materials are used the anode, the cathode or the electrolyte, and the secondary batteries may be made in the form of an angular shape, a cylindrical shape or a thin plate.
The active material is coated on both sides or one side of the electrode substrate supplied from an electrode substrate roll in even thickness, and then, is dried to be fixed. The electrode substrate on which an active material layer is formed is pressed by a roll heated at temperature of 80° C. to 150° C. to be formed into a basic electrode structure. The electrode structure is wound on a winding roll, and then, passes through a predetermined process in order to be used in a secondary battery assembling process.
In this instance, in order to continuously make the electrode of the secondary battery when the electrode of the secondary battery is made into a roll type, a termination end of an electrode substrate roll of the front end and a start end of an electrode substrate roll of the rear end are connected with each other, and in this instance, they are generally connected by an adhesive tape whose lower surface is coated with an adhesive.
However, in a case that the electrode substrate rolls are connected with each other using the conventional adhesive tape for connecting secondary battery electrodes, the adhesive coated on the lower surface of the adhesive tape leaks out of the adhesive tape by heat or pressure while the adhesive tape goes through various processes, such as heating or pressing, and it causes production of bad secondary battery electrodes. Alternatively, the adhesive leaks to the electrode substrate part wound near to the electrode substrate on which the adhesive tape is adhered when the electrode substrates are rolled after the connecting work, and it causes damage of the electrode substrates which are wound once or more at the part where the adhesive tape is adhered.
Moreover, because the leaking adhesive may be adhered onto various processing devices, such as a press or a roll, the processing devices may break down. So, in order to prevent breakdown of the processing devices, a worker must frequently clean or maintain the devices, but it deteriorates production efficiency.
Furthermore, in a case that the electrode substrate rolls are connected with each other using the conventional adhesive tape and the electrode structure is formed through the required processing process and is wound on the winding roll, both ends of the connected part where the electrode substrate rolls are connected using the adhesive tape are cut. However, in this instance, because not only the part where the adhesive tape is adhered but also the area where the leaking adhesive is exposed are cut to be abandoned, the electrodes are wasted.
Additionally, in the case that the electrode substrate rolls are connected with each other using the conventional adhesive tape, in the process of winding the electrode substrate rolls on the winding roll after passing through the post-processing, when the both ends of the connected part must be cut. However, because the processing device cannot automatically recognize the part where the adhesive tape is adhered, the worker must check and handle the electrode substrate rolls one by one and it deteriorates production efficiency.